ALTERNATIVE GREY WATER SYSTEMS
“When dealt with appropriately, graywater is a valuable
resource which horticultural and agricultural growers, as well as home
gardeners, will increasingly come to appreciate.”
There are two concepts that sum up this book: 1) one organism’s excretions are another organism’s food, and 2) there is no waste in nature. We humans need to understand what organisms will consume our excretions if we are to live in greater harmony with the natural world. Our excretions include humanure, urine, and other organic materials that we discharge into the environment, such as “graywater,” which is the water resulting from washing or bathing. Graywater should be distinguished from “blackwater,” the water that comes from toilets. Graywater contains recyclable organic materials such as nitrogen, phosphorous, and potassium. These materials are pollutants when discarded into the environment. When responsibly recycled, however, they can be beneficial nutrients.
My first exposure to an “alternative” wastewater system occurred on the Yucatan Peninsula of Mexico in 1977. At that time, I was staying in a tent on a primitive, isolated, beach-front property lined with coconut palms and overlooking the turquoise waters and white sands of the Caribbean. My host operated a small restaurant with a rudimentary bathroom containing a toilet, sink, and shower, primarily reserved for tourists who paid to use the room. The wastewater from this room drained from a pipe, through the wall, and directly into the sandy soil outside, where it ran down an inclined slope out of sight behind the thatched pole building. I first noticed the drain not because of the odor (there wasn’t any that I can remember), but because of the thick growth of tomato plants that cascaded down the slope where the drain was located. I asked the owner why he would plant a garden in such an unlikely location, and he replied that he didn’t plant it at all — the tomatoes were volunteers; the seeds sprouted from human excretions. He admitted that whenever he needed a tomato, he didn’t have to go far to get one. This is not an example of sanitary wastewater recycling, but it is an example of how wastewater can be put to constructive use, even by accident.
From there, I traveled to Guatemala, where I noticed a similar wastewater system, again at a crude restaurant at an isolated location in the Peten jungle. The restaurant’s wastewater drain irrigated a small section of the property separate from the camp sites and other human activities, but plainly visible. That section had the most luxurious growth of banana plants I had ever seen. Again, the water proved to be a resource useful in food production, and in this case, the luxurious growth added an aesthetic quality to the property, appearing as a lush tropical garden. The restaurant owner liked to show off his “garden,” admitting that it was largely self-planted and self-perpetuating. “That’s the value of drain water,” he was quick to point out, and its value was immediately apparent to anyone who looked.
All wastewater contains organic materials, such as food remnants and soap. Microorganisms, as well as plants and macroorganisms, consume these organic materials and convert them into beneficial nutrients. In a sustainable system, wastewater is made available to natural organisms for their benefit. Recycling organic materials through living organisms naturally purifies water.
In the US, the situation is quite different. Household wastewater typically contains all the water from toilet flushings (blackwater) as well as water from sink, bathtub, and washing machine drains (graywater). To complicate this, many households have in-sink garbage disposals. These contraptions grind up all of the organic food material that could otherwise be composted, then eject it out into the drain system. Government regulators assume the worst case scenario for household wastewater (lots of toilet flushings, lots of baby diapers in the wash, and lots of garbage in the disposal unit), then they draft regulations to accommodate this scenario. Wastewater is considered a public health hazard which must be quarantined from human contact. Typically, the wastewater is required to go directly into a sewage system, or, in suburban and rural locations, into a septic system.
A septic system generally consists of a concrete box buried underground into which household wastewater is discharged. When the box fills and overflows, the effluent drains into perforated pipes that allow the water to percolate into the soil. The drain field is usually located deep enough in the soil that surface plants cannot access the water supply.
In short, conventional drainage systems isolate wastewater from natural systems, making the organic material in the water unavailable for recycling. At wastewater treatment plants (sewage plants), the organic material in the wastewater is removed using complicated, expensive procedures. Despite the high cost of such separation processes, the organic material removed from the wastewater is often buried in a landfill.
The alternatives should be obvious. Albert Einstein once remarked that the human race will require an entirely new manner of thinking if it is to survive. I am inclined to agree. Our “waste disposal” systems must be rethought. As an alternative to our current throw-away mentality, we can understand that organic material is a resource, rather than a waste, that can be beneficially recycled using natural processes.
In pursuing this alternative, the first step is to recycle as much organic material as possible, keeping it away from waste disposal systems altogether. We can eliminate all blackwater from our drains by composting all human manure and urine. We can also eliminate almost all other organic material from our drains by composting food scraps. As such, one should never use an in-sink garbage disposal. As an indication of how much organic material typically goes down a household drain, consider the words of one composting toilet manufacturer, “New regulations will soon demand that septic tanks receiving flush toilet and garbage disposal wastes be pumped out and documented by a state certified septage hauler every three years. When toilet and garbage solids and their associated flush water is removed from the septic system, and the septic tank is receiving only graywater, the septic tank needs pumping only every twenty years.” 1 According to the US EPA, household garbage disposals contribute 850% more organic matter and 777% more suspended solids to wastewater than do toilets.2
The second step is to understand that a drain is not a waste disposal site; it should never be used to dump something to “get rid of it.” This has unfortunately become a bad habit for many Americans. As an example, a friend was helping me process some of my home-made wine. The process created five gallons of spent wine as a by-product. When I had my back turned, the fellow dumped the liquid down the sink drain. I found the empty bucket and asked what happened to the liquid that had been in it. “I dumped it down the sink,” he said. I was speechless. Why would anyone dump five gallons of food-derived liquid down a sink drain? But I could see why. My friend considered a drain to be a waste disposal site, as do most Americans. This was compounded by the fact that he had no idea what to do with the liquid otherwise. My household effluent drains directly into a constructed wetland which consists of a graywater pond. Because anything that goes down that drain feeds a natural aquatic system, I am quite particular about what enters the system. I keep all organic material out of the system, except for the small amount that inevitably comes from dishwashing and bathing. All food scraps are composted, as are grease, fats, oils, and every other bit of organic food material our household produces (every food item compost educators tell you “not to compost” ends up down a drain or in a landfill otherwise, which is foolish; in our household, it all goes into the compost). This recycling of organic material allows for a relatively clean graywater that can be easily remediated by a constructed wetland, soilbed, or irrigation trench. The thought of dumping something down my drain simply to dispose of it just doesn’t fit into my way of thinking. So I instructed my friend to pour any remaining organic liquids onto the compost pile. Which he did. I might add that this was in the middle of January when things were quite frozen, but the compost pile still absorbed the spent wine. In fact, that winter was the first one in which the active compost pile did not freeze. Apparently, the 30 gallons of liquid we doused it with kept it active enough to generate heat all winter long.
Step three is to eliminate the use of all toxic chemicals and non-biodegradable soaps in one’s household. Chemicals could find their way down the drains and out into the environment as pollutants. The quantity and variety of toxic chemicals routinely dumped down drains in the US is both incredible and disturbing. We can eliminate a lot of our wastewater problems by simply being careful what we add to our water. Many Americans do not realize that most of the chemicals they use in their daily lives and believe to be necessary are not necessary at all. They can simply be eliminated. This is a fact that will not be promoted on TV or by the government (including schools), because the chemical industry might object. I am quite sure that you, the reader, don’t care whether the chemical industry objects or not. Therefore, you willingly make the small effort necessary to find environmentally benign cleaning agents for home use.
Cleaning products that contain boron should not be used with graywater recycling systems because boron is reportedly toxic to most plants. Liquid detergents are better than powdered detergents because they contribute less salts to the system.3 Water softeners may not be good for graywater recycling systems because softened water reportedly contains more sodium than unsoftened water, and the sodium may build up in the soil, to its detriment. Chlorine bleach or detergents containing chlorine should not be used, as chlorine is a potent poison. Drain cleaners, and products that clean porcelain without scrubbing should not be drained into a graywater recycling system.
Step four is to reduce our water consumption altogether, thereby reducing the amount of water issuing from our drains. This can be aided by collecting and using rainwater, and by recycling graywater through beneficial, natural systems.
The “old school” of wastewater treatment, still embraced by most government regulators and many academics, considers water to be a vehicle for the routine transfer of waste from one place to another. It also considers the accompanying organic material to be of little or no value. The “new school,” on the other hand, sees water as a dwindling, precious resource that should not be polluted with waste; organic materials are seen as resources that should be constructively recycled. My research for this chapter included reviewing hundreds of research papers on alternative wastewater systems. I was amazed at the incredible amount of time and money that has gone into studying how to clean the water we have polluted with human excrement. In all of the research papers, without exception, the idea that we should simply stop defecating in water is never suggested.
The change from a water polluting, waste-disposal way of life to an environmentally benign, resource-recovery way of life will not occur from the “top down.” Many government authorities and scientists take our wasteful, polluting way of life for granted, and even defend it. Those of us who are courageous enough to be different and who insist upon environmentally friendly lifestyles represent the first wave in the emerging lifestyle changes which we must all inevitably embrace. As our numbers increase, our cumulative impact will become more and more significant.
“The question of residential water conservation is not one of
whether it will occur, but rather a question of how rapidly it will occur.”
Martin M. Karpiscak et al.
It is estimated that 42 to 79% of household graywater comes from the bathtub and shower, 5 to 23% from laundry facilities, 10 to 17% from the kitchen sink or dishwasher, and 5 to 6% from the bathroom sink. [By comparison, the flushing of toilets (creating blackwater) constitutes 38 to 45% of all interior water use in the US, and is the single largest use of water indoors. On average, a person flushes a toilet six times a day.6]
Various studies have indicated that the amount of graywater generated per person per day varies from 25 to 45 gallons (96 to 172 liters), or 719 to 1,272 gallons (2,688 to 4,816 liters) per week for a typical family of four.4 In California, a family of four may produce 1300 gallons of graywater in a week.5 This amounts to nearly a 55 gallon drum filled with sink and bath water by every person every day, which is then drained into a septic or sewage system. This estimate does not include toilet water. Ironically, the graywater we dispose of can still be useful for such purposes as yard, garden, and greenhouse irrigation. Instead, we dump the graywater into the sewers and use drinking water to irrigate our lawns.
Reuse of graywater for landscape irrigation can greatly reduce the amount of drinkable water used during the summer months when landscape water may constitute 50-80% of the water used at a typical home. Even in an arid region, a three person household can generate enough graywater to meet all of their irrigation needs.7 In Tucson, Arizona, for example, a typical family of three uses 123,400 gallons of municipal water per year.8 It is estimated that 31 gallons of graywater can be collected per person, per day, amounting to almost 34,000 gallons of graywater per year for the same family.9 An experimental home in Tucson, known as Casa del Aqua, reduced its municipal water use by 66% by recycling graywater and collecting rainwater. Graywater recycling amounted to 28,200 gallons per year, and rainwater collection amounted to 7,400 gallons per year.10 In effect, recycled graywater constitutes a “new” water supply by allowing water that was previously wasted to be used beneficially. Water reuse also reduces energy and fossil fuel consumption by requiring less water to be purified and pumped, thereby helping to reduce the production of global warming gases such as carbon dioxide.
Because graywater can be contaminated with fecal bacteria and chemicals, its reuse is prohibited or severely restricted in many states. Since government regulatory agencies do not have complete information about graywater recycling, they assume the worst-case scenario and simply ban its reuse. This is grossly unfair to those who are conscientious about what they put down their drains and who are determined to conserve and recycle water. Graywater experts contend that the health threat from graywater is insignificant. One states, “I know of no documented instance in which a person in the US became ill from graywater.” 11 Another adds, “Note that although graywater has been used in California for about 20 years without permits, there has not been one documented case of disease transmission.” 12 The health risks from graywater reuse can be reduced first by keeping as much organic material and toxic chemicals out of your drains as possible, and second, by filtering the graywater into a constructed wetland, soilbed, or below the surface of the ground so that the graywater does not come into direct human contact, or in contact with the edible portions of fruits and vegetables.
In November of 1994, legislation was passed in California that allowed the use of graywater in single family homes for subsurface landscape irrigation. Many other states do not currently have any legislation regulating graywater (see Appendix 3). However, many states are now realizing the value of alternative graywater systems and are pursuing research and development of such systems. The US EPA, for example, considers the use of wetlands to be an emerging alternative to conventional treatment processes.
Graywater can contain disease organisms which originate from fecal material or urine entering bath, wash, or laundry water. Potential pathogens in fecal material and urine, as well as infective doses, are listed in Chapter 7.
Indicator bacteria such as E. coli reveal fecal contamination of the water, as well as the possible presence of other intestinal disease-causing organisms. Fecal coliforms are a pollution indicator. A high count is undesirable and indicates a greater chance of human illness resulting from contact with the graywater. Plant material, soil, and food scraps can contribute to the total coliform population, but fecal coliforms indicate that fecal material is also entering the water system. This can come from baby diapers, or just from bathing or showering.
More microorganisms may come from shower and bath graywater than from other graywater sources. Studies have shown that total coliforms and fecal coliforms were approximately ten times greater in bathing water than in laundry water (see Figure 9.1).13
One study showed an average of 215 total coliforms per 100 ml and 107 fecal coliforms per 100 ml in laundry water; 1810 total coliforms and 1210 fecal coliforms per 100 ml in bath water; and 18,800,000 colony forming units of total coliforms per 100 ml in graywater containing household garbage (such as when a garbage disposal is used).14 Obviously, grinding and dumping food waste down a drain greatly increases the bacterial population of the graywater.
Due to the undigested nature of the organic material in graywater, microorganisms can grow and reproduce in the water during storage. The numbers of bacteria can actually increase in graywater within the first 48 hours of storage, then remain stable for about 12 days, after which they slowly decline (see Figure 9.2).15
For maximum hygienic safety, follow these simple rules when using a graywater recycling system: don’t drink graywater; don’t come in physical contact with graywater (and wash promptly if you accidently do come in contact with it); don’t allow graywater to come in contact with edible portions of food crops; don’t allow graywater to pool on the surface of the ground; and don’t allow graywater to run off your property.
PRACTICAL GRAYWATER SYSTEMS
The object of recycling graywater is to make the organic nutrients in the water available to plants and microorganisms, preferably on a continuous basis. The organisms will consume the organic material, thereby recycling it through the natural system.
It is estimated that 30 gallons of graywater per person per day will be produced from a water-conservative home. This graywater can be recycled either indoors or outdoors. Inside buildings, graywater can be filtered through deep soil beds, or shallow gravel beds, in a space where plants can be grown, such as in a greenhouse.
Outdoors, in colder climates, graywater can be drained into leaching trenches that are deep enough to resist freezing, but shallow enough to keep the nutrients within the root zones of surface plants. Freezing can be prevented by applying a mulch over the subsurface leaching trenches. Graywater can also be circulated through evapotranspiration trenches (Figure 9.3), constructed wetlands (Figures 9.4, 9.5, 9.6, and 9.7), mulch basins (Figure 9.10), and soilbeds (Figures 9.11, 9.12, 9.13, and 9.14).
Plants can absorb graywater through their roots and then transpire the moisture into the air. A graywater system that relies on such transpiration is called an Evapotranspiration System. Such a system may consist of a tank to settle out the solids, with the effluent draining or being pumped into a shallow sand or gravel bed covered with vegetation. Canna lilies, iris, elephant ears, cattails, ginger lily, and umbrella tree, among others, have been used with these systems. An average two bedroom house may require an evapotranspiration trench that is three feet wide and 70 feet long. One style of evapotranspiration system consists of a shallow trench lined with clay or other waterproof lining (such as plastic), filled with an inch or two of standard gravel, and six inches of pea gravel. Plants are planted in the gravel, and no soil is used.
Other systems, such as the Watson Wick (Figure 9.3), may be deeper and may utilize topsoil.
The system of planting aquatic plants such as reeds or bulrushes in a wet (often gravel) substrate medium for graywater recycling is called a “constructed wetland” or “artificial wetland.” The first artificial wetlands were built in the 1970s. By the early 1990s, there were more than 150 constructed wetlands treating municipal and industrial wastewater in the US.
According to the US Environmental Protection Agency, “Constructed wetlands treatment systems can be established almost anywhere, including on lands with limited alternative uses. This can be done relatively simply where wastewater treatment is the only function sought. They can be built in natural settings, or they may entail extensive earthmoving, construction of impermeable barriers, or building of containment such as tanks or trenches. Wetland vegetation has been established and maintained on substrates ranging from gravel or mine spoils to clay or peat . . . Some systems are set up to recharge at least a portion of the treated wastewater to underlying ground water. Others act as flow-through systems, discharging the final effluent to surface waters. Constructed wetlands have diverse applications and are found across the country and around the world. They can often be an environmentally acceptable, cost-effective treatment option, particularly for small communities.” 16
A wetland, by definition, must maintain a level of water near the surface of the ground for a long enough time each year to support the growth of aquatic vegetation. Marshes, bogs, and swamps are examples of naturally occurring wetlands. Constructed wetlands are designed especially for pollution control, and exist in locations where natural wetlands do not.
Two types of constructed wetlands are in common use today. One type exposes the water’s surface (Surface Flow Wetland, Figure 9.6), and the other maintains the water surface below the level of the gravel (Subsurface Flow Wetland, Figures 9.4, 9.5, and 9.7). Some designs combine elements of both. Subsurface flow wetlands are also referred to as Vegetated Submerged Bed, Root Zone Method, Rock Reed Filter, Microbial Rock Filter, Hydrobotanical Method, Soil Filter Trench, Biological-Macrophytic Marsh Bed, and Reed Bed Treatment.17
Subsurface flow wetlands are considered to be advantageous compared to open surface wetlands, and are more commonly used for individual households. By keeping the water below the surface of the gravel medium, there is less chance of odors escaping, less human contact, less chance of mosquito breeding, and faster “treatment” of the water (due to more of the water being exposed to the microbially populated gravel surfaces and plant roots). The subsurface water is also less inclined to freeze during cold weather.
Constructed wetlands generally consist of one or more lined beds, or cells. The gravel media in the cells should be as uniform in size as possible and should consist of small to medium size gravel or stone, from one foot to three feet in depth. A layer of sand may be used either at the top or the bottom of a gravel medium, or a layer of mulch and topsoil may be applied over the top of the gravel. In some cases, gravel alone will be used with no sand, mulch, or topsoil. The sides of the wetlands are bermed to prevent rainwater from flowing into them, and the bottom may be slightly sloped to aid in the flow of graywater through the system. A constructed wetland for a household, once established, requires some maintenance, mainly the annual harvesting of the plants (which can be composted).
In any case, the roots of aquatic plants will spread through the gravel as the plants grow. The most common species of plants used in the wetlands are the cattails, bulrushes, sedges, and reeds. Graywater is filtered through the gravel, thereby keeping the growing environment wet, and bits of organic material from the graywater become trapped in the filtering medium. Typical retention times for graywater in a subsurface flow wetland system range from two to six days. During this time, the organic material is broken down and utilized by microorganisms living in the medium and on the roots of the plants. A wide range of organic materials can also be taken up directly by the plants themselves.
Bacteria, both aerobic and anaerobic, are among the most plentiful microorganisms in wetlands and are thought to provide the majority of the wastewater treatment. Microorganisms and plants seem to work together symbiotically in constructed wetlands, as the population of microorganisms is much higher in the root areas of the plants than in the gravel alone. Dissolved organic materials are taken up by the roots of the plants, while oxygen and food are supplied to the underwater microorganisms through the same root system.18
Aquatic microorganisms have been reported to metabolize a wide range of organic contaminants in wastewater, including benzene, napthalene, toluene, chlorinated aromatics, petroleum hydrocarbons, and pesticides. Aquatic plants can take up, and sometimes metabolize, water contaminants such as insecticides and benzene. The water hyacinth, for example, can remove phenols, algae, fecal coliforms, suspended particles, and heavy metals including lead, mercury, silver, nickel, cobalt, and cadmium from contaminated water. In the absence of heavy metals or toxins, water hyacinths can be harvested as a high-protein livestock feed. It can also be harvested as a feedstock for methane production. Reed-based wetlands can remove a wide range of toxic organic pollutants.19 Duckweeds also remove organic and inorganic contaminants from water, especially nitrogen and phosphorous.20
When the outdoor air temperature drops below a certain point (during the winter months in cold climates), wetland plants will die and microbial activity will drop off. Therefore, constructed wetlands will not provide the same level of water treatment year round. Artificial wetlands systems constitute a relatively new approach to water purification, and the effects of variables such as temperature fluctuations are not completely understood. Nevertheless, wetlands are reported to perform many treatment functions efficiently in winter. One source reports that the removal rates of many contaminants are unaffected by water temperature, adding, “The first two years of operation of a system in Norway showed a winter performance almost at the same level as the summer performance.” Some techniques have been developed to insulate wetland systems during the colder months. For example, in Canada, water levels in wetlands were raised during freezing periods, then lowered after a layer of ice had formed. The cattails held the ice in place, creating an air space over the water. Snow collected on top of the ice, further insulating the water underneath.21
It is estimated that one cubic foot of artificial wetland is required for every gallon per day of graywater produced. For an average single bedroom house, this amounts to about a 120 square foot system, one foot deep. However, it is better to overbuild a system than to underbuild. Some constructed wetland situations may not have enough drainage water from a residence to keep the system wet enough. In this case, extra water may be added from rain water collection or other sources.
Aquatic plants used in constructed wetland systems can be divided into two general groups: microscopic and macroscopic. Most of the microscopic plants are algae, which can be either single cell (such as Chlorella or Euglena) or filamentous (such as Spirulina or Spyrogyra).
Macroscopic (larger) plants can grow under water (submergent) or above water (emergent). Some grow partially submerged and some partially emerged. Some examples of macroscopic aquatic plants are reeds, bulrushes, water hyacinths, and duckweeds (see Figure 9.8 and Table 9.1). Submerged plants can remove nutrients from wastewaters, but are best suited in water where there is plenty of oxygen (water with a high level of organic material tends to be low in oxygen due to extensive microbial activity).
Examples of floating plants are duckweeds and water hyacinths. Duckweeds can absorb large quantities of nutrients. Small ponds that are overloaded with nutrients such as farm fertilizer run-off can often be seen choked with duckweed, appearing as a green carpet on the pond’s surface. In a two and a half acre pond, duckweed can absorb the nitrogen, phosphorous, and potassium from the excretions of 207 dairy cows. The duckweed can eventually be harvested, dried, and fed back to the livestock as a protein-rich feed. Livestock can even eat the plants directly from a water trough.22
Algae work in partnership with bacteria in aquatic systems. Bacteria break down complex nitrogen compounds and thereby make the nitrogen available to algae. Bacteria also produce carbon dioxide which is utilized by the algae.23
SOILBOXES OR SOILBEDS
A soilbox is a box designed to allow graywater to filter through it while plants grow on top of it (Figure 9.14). Such boxes have been in use since the 1970s. Since the box must be well-drained, it is first layered with rocks, pea gravel, or other drainage material. This is covered with screening, then a layer of coarse sand is added, followed by finer sand; two feet of top soil is added to finish it off. Soilboxes can be located indoors or outdoors, either in a greenhouse, or as part of a raised-bed garden system.24
Soilboxes (soilbeds) located in indoor greenhouses are illustrated in Figures 9.11 and 9.13. An outdoor soilbed is illustrated in Figure 9.12.
At one point in the development of my homestead, I had to decide what to do with my graywater. My household produced no blackwater or sewage, and we composted all of our organic material. We only had a hand pump at the kitchen sink, and we carried our drinking water from a spring out behind the house. Nevertheless, we still had a sink and bathtub with drains, and the water had to go somewhere.
The choices I had were pretty limited: install an underground septic tank and drain the graywater into it; run the graywater through some sort of biofilter (such as sawdust) and then compost the sawdust on occasion; or try some sort of constructed wetland. I decided to experiment with the last option, mainly because I had an acid-mine-drainage spring running past my house, and I thought the graywater, which tends to be alkaline because of soap, would help neutralize the acid water. I also thought a pond would provide insurance against a drought, when rain water collection for watering a garden isn’t reliable.
The acid spring flowed past my house from an abandoned surface coal mine, and when I first started living beside it, it was choked with long, slimy, green algae. I introduced ducks to the algae-choked water, and quite by accident, I found that the algae disappeared as long as I kept ducks on the water. Whether the ducks were eating the algae or just breaking it up with their feet, I don’t know. In any case, the water changed from ugly to beautiful, almost overnight, by the simple addition of another lifeform to the biological system. This indicated to me that profound changes could occur in ecological systems with proper (even accidental) management. Unfortunately, constructed wetland systems are still new and there is not much concrete information about them that is applicable to single family dwellings. Therefore, I was forced, as usual, to engage in experimentation.
I built a naturally clay-lined pond near my house about the size of a large swimming pool, then diverted some of the acid mine water to fill the pond. I directed my graywater into this “modified lagoon” wastewater system via a six inch diameter drain pipe with an outlet discharging the graywater below the surface of the pond water. I installed a large drainpipe to act as a pre-digestion chamber where organic material could collect and be broken down by anaerobic bacteria en route to the lagoon, like a mini septic tank. I add septic tank bacteria to the system annually by dumping it down the household drains. I assumed that the small amount of organic matter that entered the pond from the graywater drain would be consumed by the organisms in the water, thereby helping to biologically remediate an extensively damaged source of water. The organic material settles into the bottom of the pond, which is about five feet at the deepest point, thereby being retained in the constructed system indefinitely. I also lined the bottom of the pond with limestone to help neutralize the incoming acid mine water.
The ducks, of course, loved the new pond. They still spend countless hours poking their heads under the water, searching the pond bottom for things to eat. Our house is located between our garden and the pond, and the water is clearly visible from the kitchen sink, as well as from the dining room on the east side of the house, while the nearby garden is visible from the west windows. Shortly after we built the pond, my family was working in our garden. Soon we heard the loud honking of Canada geese in the sky overhead, and watched as a mating pair swooped down through the trees and landed on our new, tiny pond. This was quite exciting, as we realized that we now had a place for wild waterfowl, a bonus we hadn’t really anticipated. We continued working in the garden, and were quite surprised to see the geese leave the pond and walk past our house toward the garden where we were busy digging. We continued to work, and they continued to walk toward us, eventually walking right past us through the yard, and on to the far end of the garden. When they reached the orchard, they turned around and marched right past us again, making their way back to the pond. To us, this was equivalent to an initiation for our new pond, a way that nature was telling us we had contributed something positive to the environment.
Of course, it didn’t end with the two Canada Geese. Soon, a Great Blue Heron landed in the pond, wading around its shallow edges on stilt-like legs. It was spotted by one of the children during breakfast, a mere fifty feet from the dining room window. Then, a pair of colorful wood ducks spent an afternoon playing in the water. This was when I noticed that wood ducks can perch on a tree branch like a songbird. Recently, I counted 40 Canada geese on the little pond. They covered its surface like a feathery carpet, only to suddenly fly off in a great rush of wings.
We raise our own domesticated ducks for algae control, for eggs, and occasionally for meat. At one point we raised some Mallard ducks, only to find that this wild strain will fly away when they reach maturity. One of the female Mallards became injured somehow, and developed a limp. She was certainly a “lame duck,” but the children liked her and took care of her. Then one day she completely disappeared. We thought a predator had killed the defenseless bird, and we never expected to see her again. To the children’s delight, the following spring a pair of wild Mallard ducks landed on our little pond. We watched them swim around for quite some time, until the female came out of the water and walked toward us. Or, I should say, “limped” toward us. Our lame Mallard duck had flown away for the winter only to come back in the spring with a handsome boyfriend! Our new graywater pond was the point of reference for her migration.
My youngest daughter, Phoebe, was given a Canada goose to raise by one of the neighbors. The tiny gosling couldn’t have been more than a day or two old when it was discovered wandering lost along the road. I’m not sure why Phoebe was asked to take care of the goose, other than she loves animals and she had a pond in her backyard, but she enthusiastically accepted the responsibility. She named the goose “Peepers,” and everywhere Phoebe went, Peepers followed. The two of them spent many a day at the graywater pond, Peepers splashing around in the water while Phoebe sat on the shore watching. Soon Peepers was a full grown goose, and everywhere Peepers went, large piles of goose droppings followed. The goose doo situation finally became so intolerable (to Dad, who renamed the goose “Poopers”) that Peepers was furtively exported to the wild. Phoebe was heartbroken.
This spring, as I write this, ten years after our graywater pond was constructed, a pair of honking Canada geese once again flew overhead. Except this time, only the female landed in our little pond. Phoebe went running to the pond when she heard that familiar honking, yelling “Peepers! Peepers!” Peepers had come back to say hello to Phoebe. How did I know it was Peepers? I didn’t. But somehow, Phoebe did. She stood on the pond bank for quite some time talking to the majestic goose, and the goose, also standing on the bank, talked back. They carried on a conversation that is rarely witnessed. Finally, Peepers flew off, and this time, Phoebe was happy.
I have more stories to tell about our graywater pond, and no doubt will have
many more in the future. A buried, quarantined, septic tank for graywater, on
the other hand, is pretty boring. I believe I made the right decision in
deciding to construct a pond for our graywater. The benefits of such a system
can go far beyond what one may imagine.
Source: The Humanure Handbook. Jenkins
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